Content-Intelligent Caching - Radware Alteon Application Manual

Alteon Application Switch Operating System Application Guide
Server Load Balancing

Content-Intelligent Caching

Web pages are composed of a series of objects. Many of these objects are static objects that are
used repeatedly from page to page. Alteon caching can recognize requests for such objects and
retrieve them directly from Alteon's local cache without fetching them from the Web server. This
relieves the server of dealing with repetitive requests for the same content and at the same time
accelerates objects delivery to the end-user.
Alteon caching support is compliant with RFC 2616 of HTTP 1.1. It respects relevant HTTP headers
(such as Cache-control, Expires, Authorization, Pragma, and so on) which are the Web Application
means of dictating which content is to be cached and when it should be refreshed.
Alteon caching has options to determine its cache behavior, both in terms of which content to cache,
and in terms of which content to serve to clients from cache. Caching support includes the option to
define per-URL caching behavior, cache expiration time, and includes an option to optimize a client
browser's caching to improve response time and Quality of Experience (QoE).
Alteon caching is based on Alteon's RAM to ensure fast retrieval of content and delivery to clients.
You can configure the amount of RAM dedicated for the caching Web object. However, the more
cache space you allocate, the fewer the number of concurrent connections that can be handled by
Alteon.
Caching occurs at the client side of the flow. This means that when a request comes, it is considered
higher priority for serving from cache before all other application services (for example, HTTP
modifications). On the other hand, when a server response arrives at the Application Services
Engine, it goes through all required treatments, such as compression and HTTP modification, before
being cached. Therefore the next serving of that response from cache also includes them.
Caching configuration includes a FastView policy and a cache URL exceptions rule list that is
optionally associated to that policy. FastView policies are, in turn, associated with an HTTP virtual
service.
This section describes the following procedures:
• Configuring the Caching Virtual Service, page 268
• Configuring the FastView Policy, page 269
Configuring the Caching Virtual Service
For Alteon to perform caching, you must define an HTTP virtual service and associate a FastView
policy to it. As with other Alteon capabilities, the virtual service is assigned to an application, in this
case HTTP, or HTTPS with SSL offloading.
To associate a caching policy to a virtual service
1. Access the Virtual Server Service menu for the virtual service to which you want to associate the
FastView policy. In the following example, Virtual Server 1 is associated with the HTTP
application.
Note: When indicating the virtual service, you can use either the virtual port number or a
name. In this example, instead of the HTTP, you can enter 80 for the standard HTTP port
number.
>> Main# /cfg/slb/virt 1/service 80/http/cachepol
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Document ID: RDWR-ALOS-V2900_AG1302